A model describing the role of transversal and longitudinal diffusion of cGMP and Ca2+ in signaling in the rod outer segment of vertebrates is developed. Utilizing a novel notion of surface-volume reaction and the mathematical theories of homogenization and concentrated capacity, the diffusion of cGMP CGMP and Ca2+ in the interdiscal spaces is shown to be reducible to a one-parameter family of diffusion processes taking place on a single rod cross section; whereas the diffusion in the outer shell is shown to be reducible to a diffusion on a cylindrical surface. Moreover, the exterior flux of the former serves as a source term for the latter, alleviating the assumption of a well-stirred cytosol. A previous model of visual transduction that assumes a well-stirred rod outer segment cytosol (and thus contains no spatial information) can be recovered from this model by imposing a "bulk" assumption. The model shows that upon activation of a single rhodopsin, cGMP changes are local, and exhibit both a longitudinal and a transversal component. Consequently, membrane current is also highly localized. The spatial spread of the single photon response along the longitudinal axis of the outer segment is predicted to be 3-5 μm, consistent with experimental data. This approach represents a tool to analyze pointwise signaling dynamics without requiring averaging over the entire cell by global Michaelis-Menten kinetics.

Andreucci, D., Bisegna, P., Caruso, G., Hamm, H.e., Dibenedetto, E. (2003). Mathematical model of the spatio-temporal dynamics of second messengers in visual transduction. BIOPHYSICAL JOURNAL, 85(3), 1358-1376 [10.1016/S0006-3495(03)74570-6].

Mathematical model of the spatio-temporal dynamics of second messengers in visual transduction

BISEGNA, PAOLO;
2003-01-01

Abstract

A model describing the role of transversal and longitudinal diffusion of cGMP and Ca2+ in signaling in the rod outer segment of vertebrates is developed. Utilizing a novel notion of surface-volume reaction and the mathematical theories of homogenization and concentrated capacity, the diffusion of cGMP CGMP and Ca2+ in the interdiscal spaces is shown to be reducible to a one-parameter family of diffusion processes taking place on a single rod cross section; whereas the diffusion in the outer shell is shown to be reducible to a diffusion on a cylindrical surface. Moreover, the exterior flux of the former serves as a source term for the latter, alleviating the assumption of a well-stirred cytosol. A previous model of visual transduction that assumes a well-stirred rod outer segment cytosol (and thus contains no spatial information) can be recovered from this model by imposing a "bulk" assumption. The model shows that upon activation of a single rhodopsin, cGMP changes are local, and exhibit both a longitudinal and a transversal component. Consequently, membrane current is also highly localized. The spatial spread of the single photon response along the longitudinal axis of the outer segment is predicted to be 3-5 μm, consistent with experimental data. This approach represents a tool to analyze pointwise signaling dynamics without requiring averaging over the entire cell by global Michaelis-Menten kinetics.
2003
Pubblicato
Rilevanza internazionale
Articolo
Sì, ma tipo non specificato
Settore ICAR/08 - SCIENZA DELLE COSTRUZIONI
Settore ING-IND/34 - BIOINGEGNERIA INDUSTRIALE
Settore BIO/10 - BIOCHIMICA
English
Con Impact Factor ISI
calcium ion; cyclic GMP; article; calcium signaling; cytosol; human; mathematical model; Michaelis constant; molecular dynamics; phototransduction; retina rod outer segment; vision; animals; calcium; cell membrane; computer simulation; cyclic GMP; cytosol; diffusion; kinetics; light; models, theoretical; photons; photoreceptors; phototransduction; rod outer segments; signal transduction; time factors; vertebrata
Andreucci, D., Bisegna, P., Caruso, G., Hamm, H.e., Dibenedetto, E. (2003). Mathematical model of the spatio-temporal dynamics of second messengers in visual transduction. BIOPHYSICAL JOURNAL, 85(3), 1358-1376 [10.1016/S0006-3495(03)74570-6].
Andreucci, D; Bisegna, P; Caruso, G; Hamm, He; Dibenedetto, E
Articolo su rivista
File in questo prodotto:
File Dimensione Formato  
Fototransduction_BJ.pdf

accesso aperto

Descrizione: Articolo
Dimensione 261.54 kB
Formato Adobe PDF
261.54 kB Adobe PDF Visualizza/Apri

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2108/23561
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 34
  • ???jsp.display-item.citation.isi??? 26
social impact